Flu vaccines ineffective in adults over 65, analyses assert

A flurry of recent studies has shown that flu shots don't offer much protection against influenza in elderly people who have received the vaccine, a recent report suggests.

A study published in January of 2012 — an analysis of all randomized controlled clinical trials testing flu vaccines between 1967 and 2011 — found that there have been no clinical trials testing efficacy among just the elderly, The Scientific American reported. In fact, the only flu vaccine that appeared to help elderly participants was a live-attenuated inhalable vaccine that is not approved for use in the United States, according to the study.

Experts consulted by The Scientific American suspect the reason for the vaccine's ineffectiveness is due to immune senescence, or the idea that peoples' immune systems weaken as they age, which makes it harder for vaccines to solicit an immune response. It makes sense that a higher-dose version of the vaccine would help this group, says epidemiologist Lisa Jackson, M.D.

“The higher dose produces a higher level of antibodies, but we don't really know what that correlates to,” Jackson told the magazine. “Until such time as the role of vaccines for preventing influenza in the elderly is clarified, more comprehensive and effective strategies for the control of acute respiratory infections should be implemented.”